vi support is built into the browser, you only need to enable vi-mode in your default-modes. There is no concept of tree tabs, you manipulate tabs as "buffers" that you can switch to via fuzzy search, which IMO is far more efficient. You can take a look at one of the core maintainers' config. Alternatively, I've recently added a Guix home service and feature into rde for those that want a more batteries-included config, which you can check how I use in my dotfiles